Fake base stations (BSs) have been used to launch many attacks on wireless communication systems, such as sending out spoofing and phishing short message service (SMS) messages, catching mobile user's device identity, or launching man-in-the-middle tacks against the mobile users. In the phishing SMS message case, innocent users are often deluded to act based on the fake information. The consequences are financial loss of end users, bad user experience to the operators, media exposure, and sometime social disturbance.